Teletypewriter automatic switching system



April 18, 1939. E. F. WATSON 2,154,592

TELETYP-EWRITER AUTOMATIC SWITQHING SYSTEM y Filed oct. 5, 1935 s she'ets-sneet 1 ATTORNEY April 18, 1939. E. F. wATsoN 2,154,592

TELETYPEWRITER AUTOMATIC SWITCHING SYSTEM Filed oct. 5, Vw35 5 sheets-sheet 2 WIWM,

NS NQ En N62 E/-T WATSON ATTORNEY April 18, 1939. E. F. wATsoN TELETYPEWRITER AUTOMATIC SWITCHING SYSTEM .3 Sheets-Sheet 3 Filed Oct. 5, 1935 /NVENTOR EE WATSON ATTORNE V Patented Apr. 1s, 1939 TELETYPEWRITER AUTOMATIC SWITCHIN G SYSTEMA Edward Fisk Watson, Larchmont, N. Y., assignor s to American Telephone and Telegraph Company, a corporation oi' New York Application October 5, 1935, Serial No. 43,790

23 Claims.

This invention relates to teletypewriter automatic switching systems, and, more particularly, to a communication system in which a transmitting teletypewriter may be automatically con- 5 nected for vsignal transmission to a line or group of lines.

In certain types of teletypewritlng service, a

considerable volume of relatively short messages are transmitted from a central broadcasting teletypewriter station over individual telegraph lines to individual teletypewriter stations or groups of stations. With ordinary systems of 0peration, it is rst necessary for an operator to connect the station or stations intended to receive the rst message to her teletypewriter.

Then the operator perforates the message on the tape by means of her perforator. As the tape passes through her transmitter-distributor, the operator watches it and, when the transmission 20 of the message has been completed, she throws keys or performs other manual operations to select the next station or stations intended to receive the next message. All this consumes considerable operating time thereby reducing the eiiciency of the operator.

Consequently, it is an object of this invention to provide an improved automatic teletypewriter i switching system for automatically connecting a sending teletypewriter to a line or group of lines for the transmission of signal impulses.

In accordance with this invention, messages are transmitted by means of perforated tape in which each message is preceded by special signals, perforated in the tape, representing the station or stations to which each particular message is to be sent. When these special signals pass through the transmitter-distributor, they automatically cause the operation of electroresponsive switching instrumentalities for connecting the desired stations to the sending teletypewriter. This closes the telegraph lines leading to those stations and lcauses their teletypewriter motors to be started.

The message perforated in the tape is then transmitted to these receiving stations. Following each message, a stop signal is perforated in the tape to effect the stopping of the teletypewriter motors at the connected receiving stations and to restore the switching instrumentalities at the sending station to the condition in which no receiving stations are connected to the sending teletypewriter. This procedure is repeated for each message until all the messages have been transmitted.

These and`other features of the invention will now be described in detail in connection with the description of the accompanying drawings in which:

Fig. 1. illustrates a teletypewriter switching system adapted to be controlled by perforated 5 tape and having selecting mechanism operated by five magnets;

Fig. 2 illustrates a modification of the invention adapted to be controlled by a remote station. and having selecting mechanism operated by a -single magnet; and

Fig. 3 illustrates a further modification ofthe invention adapted to be controlled by a tape reperforator operated by signals sent from another station.

In Fig. 1, the tape perforator IUU at station A is arranged to make signiiicant perforations in a transmitting tape IUI in accordance with a six unit code. The lower ve units of the code shown on the tape IUI are used to operate selecting mechanism'in teletypewriters at outlying teleiypewriter stations, such as 6U, 6I, 62 and 63. The top, or sixth, unit of the code shown on the tape IUI is employed for controlling the switching of the normally open transmission channels 25 6, 1, 8 and 9. In the middle of the tape IUI are feed holes 48 for enabling tape IUI to be fed by a sprocket Wheel feeding mechanism (not shown).

Station A has a signal sending device, such as a transmitter-distributor, the operation of which is controlled by the perforations in tape IUI. This signal sending device is shown to comprise a transmitter IU8 having six contacts IU to I5, inclusive. The contacts IU to I4 correspond to 35 the five selecting units of the code perforated in tape IUI. The contact I5 corresponds to the sixth code perforation in tape IUI. Contacts IU to I4 of transmitter IUU are connected to armatures I to 5, respectively, of slow-to-release 40 relay 2U. Normally, relay 2U is unoperated and its armatures I to 5 connect contacts IU to I4 to segments 'I3 to 'Il of distributor 4U.

When relay 2U is operated, armatures I to 5 connect contacts IU to I4 to selecting magnets 23 to 21 of a printer type of mechanism, such as that described in Patent 1,665,594 granted April 10, 1928, to H. L. Krum, which is hereby incorporated and made a part of this specification. These ve magnets operate selecting mechanism (not shown) for selecting any one of up to thirty-one pull bars represented schematiutor 40 by means of shaft 42 driven by motor 4I.

The transmitter-distributor also comprises a distributor 40 with a rotatable brush arm 19 and a face-plate having a common ring 18 and a segmented ring having seven segments 1| to 1.1, inclusive. Of the seven segments of this segmented ring, segment 1I is the stop segment, 12 is the start segment. and 13 to 11 are selecting segments. The brush arm 19 of distributor 40 is secured to a 'friction driven shaft (not shown) and is normally engaged by detent 10 on the armature oi the start magnet 29.

When start magnet 29 is energized, such as by manually closing switch 41, it operates its armature and causes the detent 10 `to release brush arm 19 which rotates until it is stopped by deenergizing magnet 29, either by manually opening switch 41 or by automatic operation of the tape control lever 49 when the tape between perforator |00 and transmitter I08 becomes taut. This method of operation is described in Patent 2,055,567, issued to me on Sept. 29,1936. Arm 19 rotates in a clockwise direction and connects the segments 1| to 11 seriatim to the common ring 19. During each revolution of the rotatable brush arm 19, a set of contacts 29 is closed at the time when the brush arm 19 is sweepingover segment I1 of the distributor face-plate.

The common ring 18 of distributor 40 is connected to both the receiving magnet 45 of the local teletypewriter 43 and to a contact of relay 2| which is designed to make beiore breaking to insure that the line will be kept closed when desred. Normally, relay 2| is unenergized and its contact connects ring 19 to resistances 36 to 39, inclusive. When relay 2| is energized, it operates its armature to close its make-before-break contact to prepare resistances 36 to 39 to be connected to battery 35 as soon as relay 34 is energized as will be described subsequently.

Each of relays 30 to 33 has an armature connected to an individual teletypewriter station 60, 6I, 62, and 63, respectively, as shown in the drawings. As many as thirty-one of these individual teletypewriter stations may be connected to the control station. However, for purposes of illustration, only four of these stations have been shown and it is to be understood that stations and 6I represent the iirst and second stations, respectively, and that stations 62 and 63 represent the thirtieth and thirty-mst stations, respectively.

In starting the transmission of a message from station A, switch 41 is closed for energizing magnet 29 and the tape IOI is perforated with the call letters of the teletypewriter stations which are to be connected to the sending station A for receiving that particular message. These call letter perforations include the sixth unit of the code and are illustrated by call letter perforations 35 and 86 in tape IOI.

When these call letter perforations pass through the transmitter |08, contact I5 closes a path for current from battery I6 to energize slowto-release relay 20 which operates its armatures. The right armature of relay 20 closes a path for current from battery I1 to energize relay 2 I. The left armatures to 5 of relay 20 open the circuits from contacts I0 to I4 of transmitter |08 to the segments 13 to 11 of distributor 40 and switch contacts I0 to I4 to selecting magnets 23 to 21 of a printer type of mechanism. As was mentioned above, this printer mechanism is similar to a teletypewriter except that the pull bars 54 to 51, correspondingto each character to be printed, are arranged so that each pull bar 64 to 51 closes one of up to thirty-one electrical contacts represented by contacts 50 to-53, instead of operating a type bar to print a character.

Assume that the station 60 is to be connected for receiving the message. Then a call letter, such as call letter 35, is transmitted. 'I'he contact I5 of the transmitter |09 closes and causes relay 20 to become energized. Operation of relay 20 causes the operationof relay 2| and transfers the left armatures o! relay 20 from the circuits leading to distributor 40 to the selecting magnets 23 to 21. The call letter 85`also eiects the selection of a mechanically operated pull bar 54 in this modied printer mechanism.

By this time, start magnet 29 has been energized by the closure oi' switch 41 and effects the release of brush arm 19 for rotation. As arm 19 sweeps over segment 11 of distributor 40, the end of arm 19 will strike against the contacts 29 and momentarily close them. This closes a path from ground I9 through contacts 29, magnet 22, contact I5 of transmitter |09, and then to grounded battery I6. Magnet 22 will now be energized and will cause the selected pull bar 54 to momentarily close contact 50. Closure of contact 50 establishes a circuit from grounded battery I9 through the left winding oi.' relay 34, contact 50, winding oi relay 30, and then to ground thereby energizing relays 30 and 34. Relay 34 locks-up over a circuit extending from ground 44 at the local teletypewriter set 43, over contact 46, through the right winding of relay 34, over the operated armature of relay 34, and then to grounded battery 35.

Relay 30 locks-up over a circuit extending from ground through the winding of relay 30, the operated top armature of relay 30, the operated armature of relay 34, and then to grounded battery 35. Operation of relay 30 closes a circuit leading from the outlyingrteletypewriter station 60 over line conductor 6, operated bottom armature of relay 30, resistance 36 which controls the current flow in line 6, operated armature of relay 2|, operated armature of relay 34, and then to grounded battery 35. Since the motor of the 'teletypewriter at station 60 is designed to start when communication path 6 becomes closed, it

now starts and conditions station 60 for the reception of messages.

During the rotation of brush arm 19 at this time, the circuits leading from segments 13 to 11 of the distributor face-plate are open at the left 'contacts of operated armatures I to 5 of relay 20 and, under these conditions, the call letter 35 is not transmitted to the local teletypewriter 43. If it is desired to record this call letter 85 on the local teletypewriter 43, this may be accomplished by omitting the left contacts of relay 20 and connecting segments 13 to 11 directly to the armatures I to 5 of relay 20.

In accordance with the usual operation of the transmitter-distributor |08 and as is described in my Patent2,r055,567 mentionedabove, the tape |0I will be advanced one step as brush arm 19 completes its rotation. Advancement of the tape |0| places the next code signal combination 86 in engagement with the transmitting contacts I0 to I 5 of transmitter |08 for operating the mechanically operated instrumentalities (the selected pull bar and its associated contact) for automatically connecting' the next station desired. Relay 20 is now energized again and, since its armature did not release immediately after call letter I8 was sent vbecause it is of the slow-torelease type, is maintained operated thereby maintaining relay 2| energized during this time. Another pull bar 65 is now selected and operated to momentarily close contact Il. 'Ihis energize! relay 3| in a manner similar to that described for the operation of relay 88. Relay 8|, in operating its armatures. locks-up and connects outlying teletypewriter station 6| to the commontransmitting point at the armature of relay 2| in a manner similar to that in which station 88 was connected. y

In a similar fashion, the control instrumentalities may be operated to connect any desired number, up to the maximum, of outlying teletypewriter stations 68 to 63 in any desired combination to the sending station A for simultaneously receiving a particular message sent by the transmitter-distributor at station A. In the teletypewriter system illustrated, the maximum capacity is limited only by the use of a ve unit permutation code selecting mechanism which aiords the possible use of thirty-two lines.

In the preferred embodiment of the invention, only thirty-one lines are used as the thirty-sec-v ond code combination is used for providing a time delay interval for giving the motors of the teletypewriters at stations 68 to 63 suiilcient time to start and attain full operating speed before transmission of the message. This thirty-second code combination is preferably that combination shown on tape |8| at point 81 and consists only of the sixth unit of the code. During the passage. of these signals 81 through transmitter |88, relay 28 remains operated, but no further action takes place. Thus, selecting magnets 23 to 21, pull bars 54 to 51, contacts 58 to 53, and relays 38 to 33 may be considered as being, in effect, a mechanically operated unattended, or automatic, switchboard.

After a sufficient number of signals 81 have been `sent tovallow the motors to reach their operating speed, a preparatory signal, or signals is transmitted. One oi' these preparatory signals is represented at point 88 on tape |8| Where it.

can be seen that it does not contain a sixth unit. Therefore, during the transmission of these preparatory signals 88, contact i5 will remain openthereby causing relay 28 to release. The release of the left armatures to 5 of relay 28 connects segments 13 to 11 of the distributor 48 to the sending contacts I8 to I4 of transmitter |88. Release of the right armature of relay 20 opens the energizing circuit of relay 2| and causes it to release its armaturewhich closes a circuit from the common distributor ring 18 over the selected telegraph lines 6 to 9 to the desired stations 68 to 63.

The message signals, suchv as that shown at point 89 on tape |8|, can now be transmitted to the selected stations 68 to 63 and also to receiving magnet of the local teletypewriter set 43. These message signals include not only the various letter combinations, such as that shown at 89, but also the carriage return combination 98, the line feed combination 9|, the shift signal 92, and after the end of `a message, the moto-r stop combination 93.

Following the transmission of the message perforated in tape |8|, a motor stop signal, as indicated at 93 on tape- |8|, is transmitted. This serves to stop the motors of the selected teletypewriters at stations 68 to 63. The motor stop signal 93, by means of the selecting apparatus of the teletypewriter, also effects the momentary opening ot contact 46 in the local teletypewriter set 48 by stunt bar I8. The opening of contact 48 opens the locking-up circuit of relay 34 which releases. This, in turn, opens the locking-up circuit of relays 88 to 88 and causes them to release their armatures and thereby open the selected lines l to 8. The system is thus restored to its normal condition.

In the preferred embodiment of the invention, it is'desirable to follow the motor stop signal 83 with a few signals 84, corresponding to signals 81, to allow suillcient time for relays. 38 to 32 to release and to restore the system to normal before beginning the selection oi stations for receiving the next message.

The selection of stations for receiving the next message is effected in a manner similar to that just described above. This procedure is repeated for all messages which are to be sent.

In Fig. 2, control station Bz, which may be either a central oilice or a subscribers station, is 1ocated at a remote point and is connected to station Az by line Le. Station Az has a receiving magnet |45, corresponding to the magnet 45 in Fig. 1, for receiving signals sent from the teletypewriter T2 at the remote station Bz. Station Az also has sending contacts 59, instead of the tape controlled contacts in Fig. l, for transmit- .ting signals to the teletypewriter T2 at station Bz.

The teletypewriter |43 at. station Aa is provided with two contacts 64 and 65, one of which is normally open and the other normally closed, for controlling the operationof an electro-responsive instrumentality, such asrelay 66. Relay 66, in turn, controls the operation of a slow-to-release relay 28 corresponding to relay 28 of Fig. l. As in Fig. l, relay |28 controls the operation of a relay |2| corresponding to relay 2| of Fig. l.

Relay |2| is provided with two armatures one of which is designed to operate a make-beforebrealr contact 61 and the other` is connected to a selecting relay 88 in a printer type of mechanism similar to that disclosed in Patent 1,745,633, granted February 4, 1930, to S. Morton et al. which is hereby incorporated and made a part of this speciiication. Relay 88 corresponds to relay 21 shown in Fig. 1 of the Morton et a1. patent. This printer type of mechanism has contacts |58 to |53, comparable to contacts 58 to 53 of Fig. 1, which are closed by pull bars |54 to |51, similar to pull bars 54 to 51 of Fig. 1, all of which comprise what may be termed an unattended automatic, or mechanical switchboard.

When an operator at the remote station B2, desires to operate this unattended switchboard, she transmits'a preassigned permutation code combination, such as that for J, from her teletypewriter T2, over line Le, through receiving magnet |45, sending contacts 59, relay 8|, and then back over line L2 to station B2. This code combination operates the teletypewriter |43- at station A2 which actuates its selecting mechanism to elevate a pull bar 82, such as that for upper case V.L.Which momentarily closes contact 64. By the termfupper case J" is meant the permutation code combination for J preceded by the permutation code combination for shifting the platen of the teletypewriter into its upper case position. A path is now closed for current from battery 83 to pass over contact 64, through relay 66, and then to ground. Relay 66 operates its armatures and locks-up over a path through contact 65 to battery 83.

In operating, relay 66 also closes its contact l I5 thereby closing a circuit for current from battery I6 to pass over contact I I 8, through relay |20, and then to ground. Relay |20 operates to connect battery ||1 to relay |2|` which becomes energized and operates its armatures. I'he outer armature of relay 2| prepares a. circuit for energizing the selected lines |06 to |09, and the inner armature prepares a circuit for energizing relay 80 from battery 68.

Since relay 8| is in the line circuit, its armaturewill follow the signiilcant current variations transmitted from station Ba and will intermittently apply current from battery 68 to the common transmitting point at contact 61 of relay |2|. In addition, current from battery 68 will pass over the operated armature of relay 8| and also over the contact 69 and operated inner armature of relay |2| and will energize selecting relay 80 in accordance with the signals `transmitted from station Bz. Thus, the signals sent from station B2 will operate relay 80 and will cause the desired contacts to be closed in the selecting mechanism.

For example, if the operator at station Bz wishes to be connected to station |60, lshe transmits the call letter assigned to station |60. 'Ihis effects the selection of pull bar |54 which, when operated, closes contact |50 thereby closing a lays |34 and |30.

key |46 by a pull bar |58 in the local teletypewriter |43. The operation of relay connects line |06 and station |60 to the common transmitting circuit and closes a path for negative current from battery to pass over the operated outer armature of relay |2| and then over line |06 to station |60 thereby starting the motor of the teletypewriter at station |60 in a manner well known in the art. Any of the other stations |6| to |63 may be connected to this common transmitting poin't in a similar manner for simultaneously receiving a message transmitted from station B2.

When the desired number of stations have been connected to the common transmitting point, the operator at station B2 sends a preassigned permutation code combination, such as that for upper case X. The receipt ofvthis signal combination causes a pull bar 84 to momentarily open the normally closed Contact 65 which opens the locking-up circuit of relay 66. As a result, relay 66 releases its armatures thereby causing the release of relays |20 and |2|. When the inner armature of relay |2| is released, it disconnects battery 68 from relay 80 and substitutes battery |95. The release of the outer armature of relay I2| closes contact 61 and connects the common transmitting circuit over the armature of relay 8| to battery 68.

As was stated above, relay 8| follows the significant current variations transmitted from station B2 and opens and closes its armature contact in accordance with the signals. This causes battery 68 to be intermittently applied to the common transmitting circuit thereby repeating the signals sent over line L out over the lines |06 to |09, which were selected, to the connected stations |60 to |63.

Following the transmission of the message signals from station B2, a motor stop signal is sent as was mentioned in the description of the operation/of the circuit shown in Fig. 1. The motor stop signal actuates pull bar |58 in the local teletypewriter |43 for opening contact |46 thereby opening the locking-up circuit of relay |34 which, upon releasing, opens the locking-up circuits of the selected relays |30 to |33. This restores the circuit to its normal condition as shown in the drawings. Y

The above procedure can be repeated for other messages in accordance with the wishes of the operator at station B. Since it is necessary to use three code combinations, upper case J and X and the motor stop signal, for controlling the operation of the mechanical switchboard and since the use of a ve-unit selecting mechanism offers 32 permutations, without using upper and lower case discrimination, a maximum of 29 lines |08 to |09 leading to 29 stations |60 to |83 may be used although only four of each have been shown in the drawings for purposes of explanation. II a larger number of lines are desired, a dierent type of selecting mechanism utilizing upper and lower case discrimination or a code of more than ve units may be used.

Fig. 3 illustrates a modification of the invention adapted to be controlled by a tape reperforator operated by signals sent from another station. The transmitter 308 is comparable to the transmitter |08 of Fig. 1 and battery 3|6 and shaft 342 correspond, respectively, to battery I6 and shaft 42 of Fig. 1. Likewise, relays 320 and 32| and stations 360 to 363 correspond to relays 20 and 2| and stations 60 to 63 of Fig. 1. Transmitter 3 08 is controlled by tape 30| perforated by a reperforator 95. 'I'his reperforater 95 is similar to the reperforator disclosed in Patent 1,884,743 granted October 25, 1932, to E. E. Kleinschmidt which is hereby incorporated and made a part of this specication. Motor 34| corresponds to motor 4| in Fig. 1 but has been provided with a gearI arrangement to enable it to drive the punch mechanism 99 as well as distributor shaft 342.

The reperforator 95 operates in response to significant currentvariations transmitted from the teletypewriter station Ba over line La to station A3. Station B3 has been shown` to be a sending and receiving station for purposes of illustration, but it is to be understood that station B3 may be a central oilice or any other type of teletypewriter station as desired. In order to provide the sixth, or control pulse, it is necessary to use an arrangement somewhat similar to that shown in a portion of Fig. 2. Therefore, relays 345 and 366 and contacts 346, 364, and 365 correspond to relays |45 and 66 and contacts |46, 64, and 65 shown in Fig. 2. Relay 366 has been provided with an extra armature 96 which controls a circuit from battery 91 through magnet 98.

The operation of this form of the invention is as follows: for ordinary messages signicant current variations are transmitted from the t'eletypewriter station B3 and travel over the line La to the reperforator 95 at station A3 where they cause reperforator .95 to periorate tape 30| in accordance with the signals transmitted from station B3. The perforated tape 30| operates the tape controlled contacts of transmitter 308 in the `same manner that the contacts of transmitter |08 in Fig. 1r are operated by the perforated tape |0|.

When it is desired to operate the switching mechanism for connecting one of the stations 360 to 363, the operator at station B3 transmits a preassigned code combination which causes'contact 364 to close the energizing circuit for relay 366 in the manner described above for relay 66. Relay 366 lockS-up through its inner armature subject to the opening of contact 365. The outer armature of relay 366 closes the energizing circuit for magnet 98 whichcauses the sixth perforation to be made in tape 30|. Now, when the operator at station Ba transmits a five-unit code combination for selecting one of the stations `360 to 363, the sixth perforation will also. be made in the tape 30| at this time because magnet 98 is energized as long as relay 366 remains locked-up. This procedure is repeateddor each of the station selecting code combinationaafter which the operator transmits the code combinationfor opening contact 365. This unlocks relay 366 and deenergizes magnet 96. Communication can now take place between station B3 and the selected stations 360 to 363 on a five-unit code basis in the manner described above. Following the transmission of the message signals from station Bs, a motor stop signal is sent as was described in the operation of the circuit shown in Fig. 1. 'I'he motor stop signal actuates a pull bar in the teletypewriter atstation Aa for momentarily opening contact 346 thereby opening the lockingup circuit of the relay similar to relay 34 in Fig 1. This opens the locking-up circuits of the relays similar to relays 30 to 33, shown in Fig. 1, thereby restoring the circuit of Fig. 3 to its normal condition as is shown in the drawings.

It is to be understood that the above Iapparatus and circuit arrangements have been shown and described in order to illustrate the invention and that various changes and modications may be made therein without departing from the scope of this invention which is to be limited only by the claims appended hereto.

What is claimed is:

l. A communication system including in combination a first teletypewriter station having a signal sending device, a plurality of other teletypewriter stations each of which has a communication channel leading to the first station, said communication channels being normally disconnected from the signal sending device at the first station, and switching apparatus at the first station including a printer type of mechanism having a plurality of pull bars for automatically eiecting the connection of any of the communication channels to the signal sending device in any combination that may be desired* for enabling a selective plurality of the stations to simultaneously receive a message sent by the signal sending device.

2. A communication system including in combination a first teletypewriter station having a transmitter-distributor and a mechanically operated switchboard, a plurality of other teletypewriter stations, each of which has a communication channel extending to the switchboard, said communication channels being normally disconnected from the transmitter-distributor at the first station, said mechanically operated `switchboard including electro-responsive means and a printer type of mechanism having a plurality of pull bars for operating said eleotro-responsive means for automatically connecting any of the communication channels to the transmitter-distributor in any combination that may be desired for the transmission by the transmitter-distributor of a message simultaneously to each of the stations intended to receive it.

3. A communication system including in ccmbination a iirst teletypewriter station having a perforator for perforating permutation code combinations in a transmitting tape, and a transmitter-distributor the operation of which is controlled by the perforations in the tape, a plurality of other teletypewriter stations each of which has a normally open communication channel leading to the iirst station, and control means controlled by the perforations in the tape for closing the communication channels in any.de sired combination for enabling a selective plurality of the stations to simultaneously receive a message sent by the transmitter-distributor, said control means including a printer type of mechanism having a plurality of pull bars and selecting mechanism responsive to the permutation code lcombinations for selectively operating said pull ars.

4. A communication system including in combination a first teletypewriter station having a perforator for making 'significant perforations in a transmitting tape and a transmitter-distributor the operation of which is controlled by the perforations in the tape, a plurality oi' other teletypewriter stations each of which has a normally open communication channel leading to the first station, and control means including a printer type oi.' mechanism having a plurality of pull bars for effecting the closing of a plurality of the communication channels in any desired combination for enabling a selective plurality of the stations to simultaneously receive a message sent by the transmitter-distributor, the particular combination of channels closed for the transmission of a message being determined by some of the perforations in the tape.

5. A transmission system comprising a first transmission station having a teletypewriter and a perforator for making code perforations ina transmitting tape, a plurality of other transmission stations each of which has both a teletypewriter and a transmission path leading to the rst station, each of said paths being normally open, a transmitter-distributor at the rst station for transmitting signiicant current variations to both the teletypewriter at the iirst station and to any of the teletypewriters at the other stations, mechanically operated instrumentalities for automatically determining which of said other stations shall receive a particular message, a printer type of mechanism having a plurality of pull bars, and selecting mechanism for selectively operating certain of the pullbars for selectively operating said instrumentalities in accordance with certain code perforations in the tape.

6. A communication system comprising in combination a iirst teletypewriter station having a perforator for making code perforations in a transmitting tape and a transmitter-distributor the operation of which is controlled by the code trol means operable bycertain of the code perforations in the tape for selectively energizing said electric relays to selectively operate some of said pull bars to close certain of the control contacts tooperate `certain of said devices for selectively connecting certain of said communication paths to the transmitter-distributor f or communication.

` cation path extending to the first teletypewriter station, each of said communication paths being normallydisconnected i'rom the transmitter-distributor at the ilrst station by a normally unenergized electro-responsive device individual to each line, each of said electro-responsive devices having an energizing circuit which is normally opened by control contacts, and control Vmeans operable by certain of the code perforations in the tape for selectively closing certain of said energizing circuits to operate certain of said devices for selectively connecting certain of said communication paths to the transmitter-distributor for communication, said control means including the pull bars of a printertype of mechanism.

8. A communication system comprising in combination a iirst teletypewriter station having a perforator for making code perforations in atransmitting tape and a transmitter-distributor the operation of which is controlled by the code periorations in 'the tape, a plurality of other `tele typewriter stations each having a communication path extending to the first teletypewriter station, each of said communication paths being normally disconnected from the transmitter-distributor at the rst station by a normally unenergized electro-responsive device individual to each line, a modified printer type of mechanism having pull bars adapted to operate control contacts, each oi said electro-responsive devices havingk an individual energizing circuit, a plurality of normally open control contacts each of which is connected into a diierent one of said energizing circuits, selecting mechanism responsive to certain of the code perforations in the tape for selectively operating certain of the pull bars to` operate their control contacts to close the energizing circuits of the selected electro-responsive devices whereby selected stations are connected to the transmitter-distributor for communication.

9. A communication system including in combination a first teletypewriter station, a second teletypewriter station having a signal sending device, a communication channel connecting the the two stations, a plurality of other teletypewriter stations each having a communication channel leading to the second station, said communication channels being normally disconnected from the signal sending device at the second station, switching apparatus for automatically connecting any of the communication channels to the signal sending device in any combination that may be desired for simultaneously receiving a message, a plurality of control contacts for controlling the operation of said switching apparatus, a printer type of mechanism having a. plurality of pull bars for operating said control contacts, and selecting mechanism at the second station responsive to significant current variations transmitted from the iirst teletypewriter station to the second teletypewriter station for operating said pull bars.

10. A communication system including in combination a rst teletypewriter station, a second teletypewriter station having a signal sending device and a reperforator, a communication channel connecting the two stations, a plurality oi' other teletypewriter stations each having a communication channel leading to the second station, said communication channels being normally disconnectedirm the signal 'sending device at the second station. switching apparatus for automatically connecting any of the communication channels to the signal sending device in any combination that may -be desired for simultaneously receiving a message, a plurality oi control contacts for controlling the operation ot said switching apparatus, a printer type of mechanism having a plurality of pull bars for operating said control contacts, and selecting mechanism at the second station responsive to signicant current variations transmitted irom the ilrst teletypewriter station to the reperiorator at the second station for operating said pull bars.

11. A communication system comprising in combination a iirst teletypewriter station having a transmitter-distributor and a periorator for making six-unit permutation code perforations in a tape, means for operating the transmitter-distributor in accordance with iive of the six units of the permutation code perforated in the tape, a plurality oi other teletypewriter stations each having a communication path extending to the rst teletypewriter station, switching means intransmission of tive-unit permutation code signal impulses, and an instrumentality at the rst station for controlling the operation of the printer type of mechanism in response to the passage through the transmitter-distributor of a sixth t*unit of the permutation code perforated in the l2. A communication system comprising in combination a first teletypewriter station having a transmitter-distributor and a perforator for making six-unit permutation code perforations in a tape, means for operating the transmitterdistributor in accordance with ve oi.' the six units of the permutation code perforated in the tape, a plurality of other teletypewriter stations each having a communication path' extending to the first teletypewriter station, switching means including a printer type of mechanism having pull bars for selectively connecting said communica- Y tion paths to the transmitter-distributor for the transmission of ve-unit permutation code signal impulses, control means for preparing a circuit leading from the transmitter-distributor to each Y of said communication paths in response to the passage through the transmitter-distributor of a sixth unit of the permutation code perforated in the tape, and an instrumentality at the iirst station for controlling the operation of the printer type of mechanism in response to the passage through the transmitter-distributor of a sixth ,unit of the permutation code perforatedin the tape.

13. A communication system comprising in combination a communication line, a rst station having a teletypewriter for transmitting permu- A tation code signals over the communication line,

,ing to the second station, switching means at the second station including a printer type of mechanism having pull bars for selectively connecting said communication paths to the said repeating means, and control means for operating the pull bars in accordance with permutation code signals transmitted by the teletypewriter at the first station and received -by the receiving device at the second station.

14. A teletypewriter system having in combination a teletypewriter station provided with a teletypewriter having a plurality of pull bars, a plurality of telegraph lines, a plurality of other teletypewriter stations connectible to the rst station by the telegraph lines and normally disconnected from each other, instrumentalities for enabling an operator at one of the teletypewriter stations to connect his teletypewriter through the first station to one o! the other teletypewriter stations, said instrumentalities including control means at the first station, and operating means for operating'the control means only in response to the reception by theteletypewriter 'at the first station of a preassigned permutation code signal that has been preceded by a different preassigned code signal, said operating means including certain of the pull bars in the teletypewriter at the `irst station.

15. A teletypewriter system having in combination a teletypewriter station provided with a teletypewriter having a plurality of pull bars, a plurality of telegraph hues, a plurality of other teletypewriter stations connectible to the rst station by the telegraph lines and normally disconnected from each other, instrumentalities for enabling an operator at one of the teletypewriter stations to connect his teletypewriter through the rst station to one of the other teletypewriter stations, said instrumentalities includingcontrol means at the first station, operating means for operatingv the control means only in response to the reception by the teletypewriter at the iirst station of a preassigned permutation code signal that has been preceded by a diierent preassigned code signal, said operating means including certain of the pull bars in the teletypewriter at the rst station, control means for discontinuing the operation of said control means in response to the reception by the teletypewriter at the iirst station of another preassigned permutation code signal, said control means including one of the pull bars in the teletypewriter at the rst station.

16. A teletypewriter system having a teletypewriter station provided with a teletypewriter ha'ving a plurality of pull bars, a plurality of other teletypewriter stations connected to the rst station by a plurality of telegraph lines, normally unoperated switching apparatus at the first station operable in response to certain preassigned permutation code signals for switching said telegraph lines, control means at the said station for conditioning the switching apparatus for effective operation and operating means for operating the control means in response to the reception by the teletypewriter at the rst station of a preassigned permutation code signal, said operating means including one of the pull bars in the teletypewriter at the rst station.

17. A teletypewriter system including in combination a iirst station, a second station, a third station, each station being provided lwith a teletypewriter having permutation code selector mechanism and also having sending mechanism and receiving mechanism together with recording mechanism, a transmission line connecting the first station and the second station, a transmission line extending between the second station and the third station, contacts at the second sta.

tion controllable by the permutation code selector mechanism thereat for switching the third station into and out of circuit relation with the rst and second stations for intercommunication with any one of said stations to the other when connected into operative circuit relation, means for operating said contacts from either the'first or second stations to connect the third station into operative circuit relation, instrumentalities for switching said third station out of operative cirv cuit relation with the other stations, and means for operating said instrumentalities from any of said three stations.

- 18. A printing telegraph system comprising in combination a first teletypewriter station, a secof said vpermutation-code selector mechanism,

means for connecting said rst and second stations into operative circuit relation independently of said switching contacts, means for operating said switching contacts from either the first or second stations for effecting the switching of said second telegraph line into operative circuit -relation with said iirst telegraph line, means for disconnecting said second telegraph line from operative circuit relation with said first telegraph line, and operating means at said additional station for effecting the operationv of said lastmentioned means.

19. A teletypewriter system including in combination a teletypewriter central ofllce having a teletypewriter with a plurality of pull bars, a plurality of telegraph lines, a plurality of teletypewriter stations normally disconnected from each other and connectible to the central oilice by the telegraph lines for the transmission and reception of permutation code signals, switching apparatus at the central oiiice for enabling an operator at one of the teletypewriter stations to connect his teletypewriter through the central ofhce to a second teletypewriter station, a control relay at the central oiice for conditioning the switching apparatus for eiective operation, and means in the teletypewriter at the central oce for enabling the operator at the rst teletypewriter station to control the energization of the control relay, said means including one of the pull bars of the teletypewriter at the central oftice.

20. A communication system including in combination a iirst teletypewriter station, a second teletypewriter station having a teletypewriter, a communication channel connecting the two stations, a plurality of other teletypewriter stations each having a communication channel leading to the second station, said communication channels being normally disconnected from the teletypewriter at the second station, a plurality of switching relays for automatically connecting a plurality of the communication tion in any combination that may be desired for simultaneously receiving a message, a control relay at the second station for controlling the operation of said switching relays, a plurality of pull bars in the teletypewriter at the second station for controlling the energization of said control-relay, and selecting mechanism in the teletypewriter at the second station responsive to signiiicant current variations transmitted from the first teletypewriter station to the second teletypewriter station for operating said pull bars.

21. A communication system including in combination a first teletypewriter station, an intermediate teletypewriter station provided with a teletypewriter having a plurality of pull bars and also provided with a signal sending device and a reperforator, a main transmission` line for connecting the two stations, a plurality of other teletypewriter stations each having a communication channel extending to the intermediate station, said communication channels being normally disconnected from the signal sending device at the intermediate station, switching apparatus for selectively connecting any of the communication channels to the signal sending device for receiving a message transmitted from the signal sending device at the intermediate station in accordance with signals transmitted from the iirst station and received by the reperforator at the intermediate station, operating means located at the intermediate station for operating the switching apparatus in accordance with signals transmitted from the iirst station, and control means for controlling the operation of said operating means, said control means including one of the pull bars in the teletypewriter mediate teletypewriter station provided with a channels to the teletypewriter at the second stabeing normally disconnected from the signal sending deyice at the intermediate station, means for operating said signal sending device in accordance with the rive-unit permutation code signals perforated in the tape by the reperforator, operating means for operating the reperforator in accordance with signals transmitted from the first station to the intermediate station, switching apparatus for selectively connecting any of the communication channels to the signal sending device in any. combination that may be desired for simultaneously receiving a message, operating means for operating said switching apparatus, control means for controlling the operation of the operating means, said control means including instrumentalities at the intermediate station for perforating a sixth unit in the transmitting tape.

23. A communication system including in combination a first teletypewriter station, an intermediate teletypewrter station provided with a teletypewriter having a plurality of pull bars and also provided with a signal repeating device, a main transmission line for connecting the two stations, a plurality of other teletypewriter stations each having a communication channel extending to the intermediate station, said communication channels being normally disconnected from the signal repeating device at the intermediate station, switching apparatus for selectively connecting any of the communication channels to the signal repeating device in any combination that may be desired for simultaneously receiving a message transmitted from the signal repeating device at the intermediate station in accordance with signals ,transmitted from the first station and received at the intermediate station, operating means located at the intermediate station for operating the switching apparatus in accordance with signals transmitted from the iirst station, and control means for controlling the operation of said operating means, said control means including one of the pull bars in the teletypewriter at the intermediate station, and instrumentalities for discontinuing the operation of the switching apparatus, said instrumentalities including another of the pull bars in the teletypewriter at the intermediate station.

EDWARD FISK WATSON. 

